It's fast becoming obvious that there is a misperception about what social networking is about. While twitter has become infiltrated with people who share micro-details of their day-to-day lives that out of context have no meaning to most, Linked-in serves as a place where most people write so they can self-promote and read themselves over and over. It's akin to talking just to hear oneself talk, and it can wear out the usefulness of all the venues if we are not careful.
Instead of pontificating madly, listen up. If you aren't asking a question and investing yourself and your listening skills in the group or community that you are hoping to be accepted in, you are not going to find many welcoming committees.
Widening your scope, opening your mind, and reaching out to a group rather than forcing yourself in is the secret to success in social networking.
Re-tweet an article of value that you found, or introduce two Linked-in connections you have. Send a customer an article that you found on a recent bout of keyword surfing, and ingratiate yourself for thinking of another's challenge instead of purporting to have the most important advice for someone you barely know.
I know that I have learned so much from my groups. I feel like I am so lucky to have been welcomed into them so that I can share in the wealth that the combined power of the group itself has to offer. Providing value to add to the dynamic should be your goal. The networking comes as the cherry on the sundae.